1. Field of the Invention
The present invention relates to a broadband wireless communication system. More particularly, the present invention relates to an apparatus and a method for transmitting a Secondary Advanced (SA) preamble to distinguish a cell identifier in a broadband wireless communication system.
2. Description of the Related Art
Nowadays, a number of wireless communication techniques are suggested as a candidate for rapid mobile communication. Among them, an Orthogonal Frequency Division Multiplexing (OFDM) scheme is reckoned as the most dominant next-generation wireless communication technology. The OFDM scheme transmits data using multiple carriers.
Using the OFDM scheme, a base station transmits pre-arranged signals so that a terminal can acquire time synchronization and identify the base station. Herein, the pre-arranged signal can be given various names according to a system. For example, the pre-arranged signal is referred to as a preamble. The terminal can acquire the time synchronization with the base station based on the preamble received from the base station and identify its base station. A location of the resource carrying the preamble is agreed between the base station and the terminal in advance. For example, the Institute of Electrical and Electronics Engineers (IEEE) 802.16m standard, which adopts the OFDM technology, defines a Primary Advanced (PA) preamble and a Secondary Advanced (SA) preamble. The PA preamble is used for the time synchronization and the SA preamble is used to identify the base station. The SA preamble includes a plurality of sub-blocks.
When the base station uses a plurality of transmit antennas to transmit the preamble, appropriate policies are necessary to determine which antenna transmits the preamble and how the sub-blocks of the preamble are distributed per antenna. The distribution of the sub-blocks determines utilization of a maximum transmit power of the antennas, which can cause imbalance of the transmit power with respect to the sub-blocks. Hence, what is needed is an efficient alternative for the base station using the transmit antennas to distribute the sub-blocks of the preamble per antenna.